Discussion of Background
Dispensing caps are extensively described in the prior art, and generally include a body capable of being mounted around a neck delineating an opening in the container. The cap further includes a lid connected to the body by means of a hinge. The body includes a dispensing aperture which is closed off by the lid when the cap is in the closed position. In the open position, the lid at least partially exposes the dispensing aperture to facilitate the withdrawal of product from the container.
Generally, in order to move from the closed position to the open position, it is necessary to hold the container in one hand while the other hand exerts pressure on a protuberant part of the lid. Preferably, this protuberant part is defined on a side diametrically opposite the hinge.
In the case where the hinge has a spring effect, the simple action of raising the lid relative to the body induces completion of the opening movement. The spring-effect hinge brings the lid to the open position provided that it is brought to an unstable balance position and a very slight movement away from this unstable position towards the open position is induced.
Dispensing caps of this kind are known, for example, from the teachings of U.S. Pat. No. 4,813,560 and U.S. Pat. No. 3,741,447.
Other dispensing caps are known, for example as in U.S. Pat. No. 4,124,151 and U.S. Pat. No. 4,911,337, in which the spring-effect hinge is obtained by engaging a ball joint on the lid into a boss on the body. The ball joint engaged in the boss forms the hinge axis about which the lid is able to pivot relative to the body. The spring effect is obtained from a resilient portion connecting an edge of the lid to an edge of the body. This resilient portion extends on a side of the hinge opposite that at which the lid is defined. In this case also, in order to induce the passage from the closed position to the open position of the lid, pressure must be exerted on a protuberant part of the lid, with the protuberant part being diametrically opposite the resilient portion.
Another type of dispensing cap is disclosed in FR 1,161,611. With this arrangement, the lid also includes a protuberant part and a hinge having a spring means. In this case, the protuberant part is defined on a side of the hinge opposite that on which the lid is defined. In order to expose the dispensing aperture, pressure is exerted on the outer surface of this protuberant part so as to create leverage.
In the embodiment taught by FR 1,161,611, the lid is capable of reverting resiliently to the closed position, but it presents a major drawback in that the open position is only obtained as long as pressure is being exerted on the protuberant part. The spring means exerts a permanent force tending to return the lid to the closed position. This spring means has no reversible unstable balance position enabling it to pass from a first stable position, for example closed, to a second stable position, for example open. In effect the spring is included within the thickness of the lid, and stiffens it. The partial opening provided by the lid is also dependent on the plastic properties of the lid inside which the spring means is disposed.
A container fitted with a cap according to FR 1,161,611 is not easy to manipulate. In effect, even though it allows the container to be held and opened with one hand. When the product is dispensed by orienting the dispensing aperture downward, with at least one finger of the hand having to hold the lid open, the hand is then forced to assume a twisted or awkward position. Moreover, with the hand grasping the container it is difficult or impossible to correctly adjust the inclination imparted to the container to a desired position given the complex position which it is compelled to assume.
Dispensing caps known in the prior art pose a number of problems. Those which can be held in the open position when the product is being dispensed can require the use of two hands in order to accomplish opening or closure of the dispensing caps. And those dispensing caps which can be opened and held with one hand pose problems in that opening can require pressure to be maintained on part of the lid.